Aquaculture system

ABSTRACT

A self-contained aquaculture system comprising a modular building defining a first main chamber for containing fish or marine invertebrates, a second swirl chamber comprising a primary filter communicating with the main chamber for removing solids from the main chamber, a drum filter for receiving and filtering water from the swirl chamber, a third biological filter chamber beneath the drum filter for receiving water therefrom and a biological filter tank. Water is pumped from the chamber. The building defines an enclosed space over the chambers, the temperature of which is controlled by an air conditioning unit. A foam fractionator, ultraviolet unit and ozone generator are used for treating the water in the main chamber.

TECHNICAL FIELD

This invention relates to aquaculture systems for growing fish, prawnsor other marine invertebrates. The present invention also relates towater treatment components used in aquaculture systems.

BACKGROUND ART

Aquaculture has commonly been conducted by growing fish, prawns andother marine invertebrates in outdoor ponds. The ponds howevereventually become polluted because faeces, uneaten food and algae worktheir way to the bottom of the ponds. This makes the ponds almostimpossible to clean. In addition large quantities of valuable water arerequired to keep these systems functional. Other disadvantages are alsoassociated with outdoor aquaculture systems. For example pests can eatstock, adverse weather conditions such as floods can cause stock loss bywashing the stock away and very hot weather can cause growth of algalblooms which can kill the stock. In addition in very hot or very coldweather, the stock will stop growing. Muddy waters or disturbed watercan also cause the stock to have an unpalatable taste.

In order to overcome the above disadvantages, indoor commercialaquaculture systems were introduced where fish or other marineinvertebrates are grown in tanks placed in large buildings or sheds.Such systems have a number of advantages. In particular, there is acontinuing circulation of the water around the system with the additionof approximately 10 percent of its water volume each week unlike inoutdoor ponds where water is pumped in and then overflows back intostreams and rivers causing added pollution. In the indoor systems, thewater temperature is attempted to be controlled by either heating thewater with probes placed into the water or by installing large chillersand pumping the water and through the chillers to cool it to the desiredtemperature to promote fast fish growth. The temperature controlequipment is relatively expensive in capital cost and also running costscan be high. An alternative is to control air temperature, however asthe tanks and associated equipment make up less than 20 percent of theair area within the building or shed, to have effective watertemperature control, very large energy absorbing equipment would in mostcases have to be used. Further, the buildings or sheds would have to befully insulated to be viable and this would mean an impractical cost inrelation to returns.

A further disadvantage of the known systems is that the buildings orsheds housing the aquiculture system resemble a maze of pipes andplumbing as water is pumped between the system components such as tanks,filters, biological filters, foam fractionators, ultraviolet watertreatment units and other water treatment components. These componentsare individual components which have to be set up in different parts ofthe building. Drainage pipes are provided on the floor and water pipesare connected to each individual tank or component. One of the majorproblems with these system is that with a large number of pipesinterconnecting the components, vibration in the pipes or simply thesuspension of pipes can creates stresses causing pipe joints to failand/or pipe fracture. If such a failure occurs, water from the tanks isquickly lost resulting in the loss of tonnes of fish stock. Furtherwherein there is a large volume of exposed piping, water temperaturelosses occur in cold climates and water temperature increases occur inhot climates resulting in massive increases in the electricity costs forcooling or heating the water. This has in many cases made the indoorsystems commercially unviable. Another disadvantage which arises is thatfish often attempt to jump out of the tanks so additional piping has tobe placed over the top of the tanks and then covered with netting toprevent fish losses.

With regards to the individual components, if ultraviolet watertreatment units are installed, they are installed into the main waterflow pump line which reduces flow thus increasing the electricityconsumption. In the foam skimmers or foam fractionators which are usedin the conventional systems, insufficient bubbles or foam is created orforced out of the top of the units. If insufficient bubbles or foam iscreated, the fractionators simply do not function. To make them functioncorrectly, high pressure high energy pumps fitted with air venturis areemployed but these do not always overcome the problem of inefficientoperation.

Drum filters have been a part of the aquaculture systems for filteringthe water of fine waste particles created from waste food, faeces, andother extraneous matter. The majority of filters are electric motordriven off central drive shafts with bearings on which the drum filteris supported for rotation. In most cases the cleaning takes placethrough a centre mounted vertical disc through which the water mustpass. The drum filters are separate units and include an outer housingwhich is specifically designed to hold the filter and its supportingcomponents and to also hold the water. Water inlets and outlets mustalso be provided along with special float switches to activate acleaning process when the water level rises.

As a general rule, during cleaning the water flow is stopped or bypassedwhich allows uncleaned water back into the fish tanks. If the water isstopped for any length of time, it can be very detrimental to the fishstock as in times of heavy stock loading, the fish can only stay alivefor around six minutes before fatalities begin to occur. Another majordrawback is that if a bearing or another major mechanical failurehappens, removal the drum filter and all of the fittings is extremelytime consuming and in many cases can lead to total stock losses.Cleaning of the current drum filters in any event is difficult as easyaccess cannot be had to the interior of the drum.

SUMMARY OF THE INVENTION

The present invention aims to provide an improved aquaculture systemwhich overcomes or at least alleviates one or more of the abovedisadvantages. The present invention also aims to provide an aquaculturesystem which incorporates improved water treatment components. Otherobjects and advantages of the invention will become apparent from thefollowing description.

The present invention thus provides in a first preferred aspect, aself-contained aquaculture system comprising a modular building, saidbuilding having a base section, a main water chamber for containing fishor other marine invertebrates formed within said base section, saidbuilding further having a top section covering at least said mainchamber and defining an enclosed space above said main chamber, watertreatment means within at least said base section of said building andadjacent said main chamber for treating water from said main chamber,means for circulating water for flow from said main chamber through saidwater treatment means and back to said main chamber, and means forcontrolling the air temperature within said enclosed space.

The base section suitably has outer side walls and at least one of theside walls of the base section defines a side wall of the main chamber.The top section or sections may includes a roof and side walls, and theside walls of the top section are suitably aligned with the side wallsof the base section.

Preferably, the base section is moulded from a mouldable material withthe at least the main chamber integrally moulded within the basesection.

The water treatment means suitably includes filtering means for removinglarger particles or solids from water in the main chamber and forremoving smaller particles from the water. The filtering means suitablyincludes a primary filter for removal of large particles and a secondaryfilter for removing smaller particles The primary filter suitablycomprises a second chamber which is located adjacent to, and receiveswater from the main chamber. Preferably first communication meansconnect the base of the main chamber to the second chamber wherebysolids gathering in the base of the main chamber may pass into thesecond chamber. Second communication means may also connect the mainchamber adjacent the water level therein to the second chamber wherebywater and solids may flow from the top level of water in the mainchamber into the second chamber. Preferably the second means comprises aspillway between the main chamber and second chamber. The water level inthe second chamber is suitably maintained at a lower level than thelevel in the main chamber such that water will flow under the influenceof gravity from the main chamber to the second chamber via the first andsecond communication means such that heavier and lighter solidscollecting at the bottom and top of the main chamber pass into thesecond chamber. Preferably the second means opens to the periphery ofthe second chamber such as to impart a swirling movement of water in thesecond chamber to assist in drawing water and solids from the mainchamber into the second chamber. The second chamber may include a drainoutlet which may be selectively opened for example under the control ofa manual or automatic valve to dump solids from the second chamber.

The second filter suitably comprises a screen filter for receiving andfiltering water from the primary filter. The secondary filter suitablycomprises a drum filter. The drum filter suitably comprises a rotatabledrum filter having a screen or mesh material about its periphery andmeans are provided for conveying water from the second chamber of theprimary filter to pass through the screen or mesh material. Suitablemeans are provided for supporting and rotating the drum filter. Suchmeans may comprise motor means for causing rotation of the drum filter.Preferably however the drum filter is driven in rotation by waterflowing in from the primary filter. The drum filter for this purpose mayinclude a plurality of circumferentially spaced members and theconveying means may include one or more water outlets adjacent the ribsto cause rotation of the drum filter. Most preferably, the drum filteris hollow and water from the primary filter conveyed internally of thedrum filter to effect rotation thereof. Preferably, thecircumferentially spaced members of the drum filter may compriselongitudinally extending ribs against which water from the primaryfilter acts to effect rotation of the drum. The ribs suitably supportthe filter screen or mesh material which extends circumferentially. Thedrum filter may comprise a pair of circular or annular end membersbetween which the ribs extend and the end members may be supported onrollers for supporting the drum filter for rotation about a horizontalaxis. The means for directing water from the primary filter into thedrum filter suitably comprises a feed duct extending from the secondchamber and longitudinally within the drum. The height of the feed ductdetermines the level of water in the second chamber as water cannot risein the second chamber above the feed duct. The duct may includegenerally radially extending duct members having outlets for directingwater against the ribs. The duct may include a baffle beyond the ductmembers to prevent water passing out of the drum filter.

Means are suitably provided for cleaning the filter screen or meshmaterial. The cleaning means may comprise means for spraying wateragainst the screen or mesh material. Alternatively or additionally, thecleaning means may comprise means for applying pressurized air againstthe filter screen or mesh material. The means for applying water and/orair against the screen or mesh material may be located above the drumand means may be provided internally of the drum beneath the water andair applying means for catching and collecting materials dislodged fromthe filter screen or mesh material and water. The means for catchingdislodged material and water may comprise a hopper internally of thedrum. The hopper may communicate with a waste line for directing thosematerials to waste. Suitably, the hopper communicates with an extendingportion of the supply duct beyond the baffle which is connected orcommunicates with waste. Means may be provided to collect solids in theextending portion of the supply duct. The hopper may extend beyond oneor opposite ends of the drum to ensure that substantially all materialdislodged from the drum is collected.

The drum filter is suitably supported over a third chamber such thatwater passing through the drum filter collects therein. The thirdchamber may include a submerged biological filter media to define afirst biological filter for biological contact and action on the watertherein which has passed through the drum filter. The third chamber maybe divided into separate sections by suitable baffles, each sectionpreferably containing a biological filter medium. An end section of thethird chamber however is preferably free of the biological filter mediumand pump means may be located therein for supplying water to the drumfilter spraying means. The pump means may be operated at regularintervals under timer control. The third chamber may include one or moreoutlets which may be selectively or automatically opened through a valveor valves to waste for draining the third chamber.

Means such as one or more pumps may be provided to convey water in thethird chamber to a second biological filter. The one or more pump meansmay be located in the end section of the third chamber. The one or morepumps serve to circulate water through the system and maintain the levelof water in the third chamber beneath the level of water in the secondchamber. An overflow drain may be provided in the third chamber to dumpwater from the chamber if it rises above a predetermined level.

The second biological filter suitably comprises a fourth chamber whichcarries a biological filter media. The fourth chamber may be dividedinto sections by baffles with each section carrying the filter media.Water from the third chamber is suitably distributed such as by sprayingover the biological filter media. Water from the third chamber may besprayed over the biological filter medium through spray bars at theupper end of the chamber. The spray bars may be fixed spray bars orrotatable spray bars. To increase biological action, means may beprovided to supply air to the fourth chamber for flow through thebiological filter media in a direction opposite to the water flowtherethrough. Preferably, the air is supplied to the fourth chamber toflow upwardly against the water flowing downwardly through thebiological filter medium. The air may be supplied to one or more airsupply ducts arranged at a lower level within the chamber. Meanssuitably in the form of one or more ducts may be provided to communicatewater in the fourth chamber back to the main chamber.

In a further embodiment, the biological filter action may be achieved bya biological contactor in the main chamber. The biological contactor maycomprise a rotatable member which rotates with movement of circulatingwater flow in the main chamber and support a biological filter mediumtherein.

At least one foam fractionator is suitably provided for treatment ofwater in the main chamber. The foam fractionator preferably comprises afifth chamber formed in a wall of the main chamber and means areprovided for supplying air to a lower portion of the fifth chamber forbubbling through water therein. Air is suitably supplied to one or moreair blocks in the lower portion of the chamber. An inlet for water fromthe main chamber is suitably provided at the upper end of the fifthchamber. An outlet from the fifth chamber is suitably provided at alower end of the fifth chamber, the outlet communicating with the mainchamber through a return line. Air may be supplied to the return line toassist in water flow back to the main chamber. The return line suitablyincludes a portion within the main chamber which extends in a directionto assist in circulating flow of water in the main chamber. The returnline portion in the main chamber may be apertured to allow controlledescape of air in the form of bubbles from the return line. The fifthchamber suitably includes a funnel member at or adjacent the upper levelof water in the fifth chamber for collecting waste entrained in bubblesat the surface of the level of water. The funnel member is suitablyconnected to waste. The funnel member may be adjustably supported forheight variations within the chamber of the foam fractionator.Alternatively, the funnel member may be supported by a float or floatsat or adjacent the level of water in the foam fractionator chamber.

Water may be supplied from the main chamber to the inlet to the chamberof the foam fractionator through an ultraviolet treatment chamber wherewater from the main chamber is subject to exposure to ultraviolet light.The ultraviolet treatment chamber which is also preferably located inthe wall of the main chamber suitably has an inlet at its lower endcommunicating with the main chamber and contains a removable ultravioletlight source.

One or more ozone reactors may be provided for supplying ozone to waterin the chamber of the foam fractionator. The ozone reactor may beprovided in a sixth chamber in the wall of the main chamber. Ozone fromthe ozone reactor/s may be supplied to the lower end of the foamfractionator chamber to bubble upwardly through that chamber. Ozone maybe supplied to an air block submerged in the chamber.

Air for supply to the foam fractionator and the further biologicalfilter is suitably provided by one or more air pumps which pump air fromwithin the building module at the internal building temperature throughthe fractionator and biological filter to thereby control thetemperature of water therein and thus in the main chamber.

The fourth chamber of the further biological filter is suitably isdefined by a tank. The tank may be supported above the main chamber suchthat water from the main chamber flows under the influence of gravityback into the main chamber. In an alternative configuration, thebiological filter tank may be arranged adjacent to the main chamber.

Air conditioning means may be provided to control the temperature andhumidity within the enclosed space of the building module and thus thetemperature of air supplied to the foam fractionators and biologicalfilter chamber. A controllable light source such as one or more lampsmay be provided above the main chamber to create artificial day andnight conditions within the building module.

In one embodiment, the second and third chamber may be provided adjacentone end of the main chamber and the space above the main chamber andsecond and third chambers may be enclosed to control the temperaturewithin the building module. Means may be provided for communicating thespace above the main chamber with the space above the second and thirdchamber. The air conditioning means may be provided to communicate withthe space above the main chamber to control the temperature in thatspace and thus the climate in the space above the second and thirdchambers. Alternatively, the air conditioning means may be provided tocommunicate with the space above the second and third chambers.

The main chamber and the second and third chambers may be in manydifferent configurations. In one configuration, the main chamber is of asubstantially rectangular or square configuration. One or more cornersof the rectangular or square main chamber may be truncated and the foamfractionators and where provided associated ultraviolet treatmentchambers and ozone reactors may be located in the truncated comers ofthe chamber or in a wall of the main chamber. In another form, the mainchamber is of elongated configuration and a central divider is providedtherein such that flow circulates around the central divider. Primaryand secondary filters may be provided at one or both ends of the mainchamber. The central divider may support one or more foam fractionatorsand where provided associated ultraviolet treatment chambers and/orozone reactors. Alternatively, the foam fractionator/s and whereprovided associated ultraviolet chambers and/or ozone reactors providedat one or both ends of the main chamber.

The building module defining the aquaculture system of the invention maybe constructed in many different configurations. For example, the mainchamber, and second and third chambers may be formed as one unit such asby being moulded from concrete, glass reinforced plastics or othermouldable material with the biological filter tank formed as a separatemoulding or unit. One or more roof and wall sections which cooperatewith the biological filter tank to define an enclosed space over themain chamber and second and third chambers may be formed as separatemouldings or units. The separate mouldings or units may be assembled andjoined to define the building module of the aquaculture system. The roofand wall sections may be provided with one or more access openingsproviding selected access to the interior of the building module asrequired.

In another configuration, the main chamber, second and third chambersand biological filter chamber may be formed in a single lower basemolding or unit with an upper roof and wall moulding or unit coveringand enclosing the chambers. The lower base moulding or unit may beextended at one or both ends from the chambers to define access areas tothe system. In another configuration, the biological filter tank may beformed as a separate moulding or unit which extends to the full heightof the building module with the space over the main chamber, second andthird chamber being enclosed by a roof and wall section. In yet a herconfiguration, each chamber may be moulded as a separate unit with theunits being assembled by being abutted against each other. A roof andwall section may then be provided to cover and enclose the assembledchambers.

In yet a further configuration, one or more biological filter tanks maybe provided to one or both sides of the main chamber and second andthird chambers which are covered by and enclosed by a roof and wallsection. The biological filter tanks may have separate roof or lidsproviding access thereto.

The roof of the building modules may be flat which permits the modulesto be stacked one above the other to form a multi-level building.

In a further preferred aspect, the present invention provides aself-contained aquaculture system comprising a modular building, saidbuilding having a base section, a main water chamber for containing fishor marine invertebrates formed within said base section, a second swirlchamber comprising a primary filter formed in said base section adjacentsaid main water chamber, means communicating said main chamber with saidsecond chamber for removing solids from water in said main chamber, finefiltering means comprising a secondary filter for receiving water andfiltering water from said second chamber, a third biological filterchamber formed within said base section adjacent said second chamber forreceiving water from said fine filter means, said building modulefurther including a top section or sections covering said main waterchamber and said second and third chambers and defining an enclosedspace or spaces over said chambers, means for circulating water for flowfrom said main chamber through said second chamber, fine filtering meansand said third chamber back to said main chamber, means for controllingthe air temperature within said enclosed space or spaces.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood and put intopractical effect reference will now be may to the company drawings whichillustrate the preferred embodiments of the invention and wherein:

FIG. 1 illustrates in perspective view, a building module defining anaquaculture system according to a first embodiment of the presentinvention;

FIG. 2 is a sectional elevational view of the building of FIG. 1;

FIG. 3 is a plan view of the base section of the building of FIG. 1 withthe position of the biological filter tank shown in dotted outline;

FIG. 4 illustrates the building of FIG. 1 with the end flaps open;

FIG. 5 illustrates the layout of the plumbing pipes of the systemincorporated in the base or foundation of the building module;

FIG. 6 illustrates in sectional view the foam fractionator andassociated ultraviolet and ozone generator units as used in the systemof FIGS. 1 to 4;

FIG. 7 is a perspective view of the drum filter for use in the systemand its manner of support;

FIG. 8 is a side view showing the drum filter and associated feed,discharge and cleaning components;

FIG. 9 is an end view in the direction A of FIG. 8;

FIG. 10 is a cut away view of the biological filter tank;

FIGS. 11, 12 and 13 illustrate in exploded schematic end view, top viewand side view respectively the components of the aquaculture system ofFIG. 1 and the plumbing therebetween;

FIG. 14 illustrates different possible orientations of the biologicalfilter;

FIGS. 15 to 17 illustrate in plan view, the aquaculture system withdifferent orientations of biological filter as in FIG. 14;

FIGS. 18 and 19 illustrate in perspective and sectional plan views analternative building module defining an aquaculture system in accordancewith a further embodiment of the invention;

FIGS. 20 to 25 illustrate in different views an alternative buildingmodule configuration defining an aquaculture system in accordance with afurther embodiment of the invention;

FIGS. 26 to 28 illustrate the manner in which the building module ofFIGS. 1 to 4 can be provided with add on end sections;

FIG. 29 is an exploded view of a building module with end sections;

FIGS. 30 and 32 illustrate in side perspective, exploded and sectionalplan views a building module defining an aquaculture system inaccordance with a further embodiment of the invention;

FIGS. 33 and 35 illustrate in exploded, sectional plan views andperspective views a building module defining an aquaculture system inaccordance with a further embodiment of the invention;

FIGS. 36 to 39 illustrate the manner in which a number of systemcomponents can be assembled to form an aquaculture system in a buildingmodule in accordance with a further embodiment of the invention;

FIGS. 40 and 41 illustrates typical aquaculture buildings which may bedefined by stacked building modules with flat roofs such as of the typeillustrated in FIGS. 30, 33 or 39;

FIGS. 42 to 49 illustrate further embodiments of building modulesdefining an aquaculture system in accordance with the invention;

FIGS. 50 and 51 illustrate in side and sectional plan view an elongatedbuilding module defining an aquaculture system in accordance with afurther embodiment of the invention;

FIGS. 52 and 53 illustrate in side and sectional plan view an elongatedbuilding module defining an aquaculture system in accordance with afurther embodiment of the invention;

FIGS. 54 and 55 illustrate in side and sectional plan view an elongatedbuilding module defining an aquaculture system in accordance with afurther embodiment of the invention;

FIGS. 56 and 57 illustrate in sectional view further forms of foamfractionator for use in the aquaculture systems of the invention;

FIGS. 58 and 59 illustrate in side and end views a further embodiment ofdrum filter for use in the aquaculture system of the invention; and

FIGS. 60 and 61 illustrates alternative drive system for the drumfilter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings and firstly to FIGS. 1 to 4, there isillustrated an aquaculture system 10 in accordance with an embodiment ofthe invention in the form of a modular building 11 comprising anddefining a main water chamber 12 for holding fish or marineinvertebrates, a swirl chamber 13 which serves as a primary filter and abiological filter/drum or screen filter chamber 14 of a secondaryfilter. The chambers 12, 13 and 14 have their bases at substantially thesame level; however the water level in each chamber is controlled suchthat the level in chamber 14 is less than the level in chamber 13 andthe level in chamber 13 is less than the level in chamber 12. This thenallows flow of water from the main chamber 12 to the swirl chamber 13and then to the chamber 14 under the influence of gravity withoutpumping. The building module 11 also is defined by a biological filtertank 15 which is elevated and located above the main chamber 12.Opposite end integral hip roof and wall sections 16 and 17 comprisingtop or upper sections of the building module 11 extend from oppositesides of the tank 15 and over the main chamber 12, and swirl chamber 13and filter chamber 14 respectively to define enclosed air spaces overthe main chamber 12 and chambers 13 and 14. The building 11 may beconstructed of any suitable materials such as steel, timber, fiberglassor any other mouldable materials, or any other materials however thepreferred material of construction is concrete suitably a concrete whichis waterproof and provides sufficient strength to the building 11 andadditionally has high insulation properties such that no additionalinsulation is required and further facilitates moulding of the tank 15and chambers 12, 13 and 14. The main chamber 12 and chambers 13 and 14may be formed as one moulding in a base section indicated generally at18 which defines the external periphery of the building module 11, andthe tank 15, and roof and wall sections 16 and 17 as separate mouldingswhich are then assembled and joined to the lower moulding 18. Oppositeend walls of the tank 15 and the side walls of the room and wallsections 16 and 17 are thus aligned with the opposite side walls of thebase section moulding 18 and the outer end walls of the roof and wallsections 16 and 17 are aligned with opposite end walls of the basesection moulding 18 to form the modular building 10. The opposite endwalls of the roof and wall sections 16 and 17 are provided with hingedpanels 19 which may be pivoted upwardly as shown in FIG. 4 to provideaccess at one end to the chamber 12 or at the other end to the chambers13 and 14. The biological filter tank 15 is also closed by upper lidpanels 20 which are hingedly mounted by central hinges 21 to enable themto be lifted to provide access to the interior of the tank 15. It willbe apparent that when the panels 19 are closed, fully enclosed airspaces are defined over the chambers which facilitates control of airand water temperature as described further below.

The main chamber 12 is of a generally rectangular or squareconfiguration having side walls 12′ which also comprise the side wallsof the base section moulding 18 with the inner corners at the junctionof adjacent walls 12′ being truncated as at 22. A spillway 23 isprovided on one side of the chamber 12 and at an elevated location toconvey water in the chamber 12 above the level of the spillway 23 intothe swirl chamber 13. This acts as a skimmer to remove any floating scumor other materials from the surface of the water in the chamber 12. Ascreen 24 of mesh-like form is provided across the spillway 23 toprevent fish from escaping from the main changer 12 into the swirlchamber 13. The main chamber 12 also includes a central drain outlet 25which communicates through a passage 26 in the floor of the main chamber12 with the periphery of the base of the swirl chamber 13 at 27 whichdirects water from the chamber 12 into the chamber 13 in a generallycircumferential direction such as to effect anti-clockwise swirlingmotion of water in the chamber 13. The passage 26 carries fish and foodwaste from the main chamber 12 into the swirl chamber 13 without the useof pumping equipment which may breakup particles within the chamber 12.The passage 26 may also have a branch line 28 through which water may bedrained from the chamber 12 under the control of a valve 29 externallyof the building module 10 (see FIG. 5), the passage 26 and branch line28 comprising pipes encapsulated in the floor slab of the buildingmodule.

The main chamber 12 also includes in the outer pair of truncated corners22, a pair of foam fractionators 30 for oxygenating and cleaning thewater in the main chamber 12. Associated with each foam fractionator 30is an ultraviolet unit 31 for killing pathogens in the water andoptionally one or more ozone reactor or generator units 32 forintroducing ozone into the water in the fractionator 30 for sterilizingthe water. The foam fractionator 30 as more clearly shown in FIG. 6includes a chamber 33 moulded or incorporated into a corner 22 in anupright attitude. The chamber 33 may be formed by a tubular pipe 34having an upper end which extends above the corner 22 and which isclosed by a removable cap 35. A return line 36 connected to the bottomof the chamber 33 extends upwardly and then through the wall of thechamber 12 and terminates in an outward flow duct 37 (see also FIG. 2)which extends in a generally circumferential direction relative to thetank 12. An air inlet 38 into the return line 36 at the lower endthereof directs a flow of air into the line 36 to assist in the flow ofwater back into the chamber 12. The duct 37 may be apertured to allowcontrolled escape of air into the chamber 12 in the form of air bubbles.

The chamber 33 communicates with the main chamber 12 via the ultravioletunit 31 which has a chamber 39 which may also be defined by a tubularpipe 40 and which houses an elongated ultraviolet light generator 41which is removably mounted in the chamber 39 by means of an end cap 42engaged with the upper end of the pipe 40. A duct 43 communicates thelower end of the chamber 39 with the main chamber 12 and a further duct44 communicates the upper end of the chamber 39 with the chamber 34.Thus the level of water in the chambers 33 and 39 is the same as thelevel of water in the chamber 12 and water before passing into thechamber 33 is exposed to ultraviolet light.

The ozone generator unit 32 also includes a chamber 45 which is alsodefined by a tubular pipe 46 located in an upstanding attitude in a tankcorner 22 and which houses an ozone reactor or generator 47. An outletduct 48 passes upwardly from the bottom of the chamber 45 and thendownwardly in the chamber 33 to terminate in an air stone 49 to injectozone into the water in the chamber 33 for passage as bubbles upwardlythrough water in the chamber 33 to expose the water therein to ozone.

A drain cone or funnel 50 is provided in the chamber 33 and is connectedto a drain pipe 51 which leads outwardly of the chamber 33 to waste orfor collection in a container if desired. Air for creating bubbles inthe chamber 33 is supplied to the lower end of the chamber 33 to airstones 52 which are suspended via air supply ducts 53 connected to anair supply manifold 54 above the chamber 33. Air is supplied to the airmanifolds 54 via piping 55 in the slab of the building 11 (see FIG. 5)connected to an air pump 56 in the air space in the building module 11within the roof and wall section 17 (see FIG. 56).

Thus water for treatment in the chamber 33 initially passes via duct 43through the ultraviolet chamber 39 where it is exposed to ultravioletlight from the generator 41 which will destroy pathogens in the waterand then the water passes through the duct 44 into the chamber 33. Airsupplied to the air stones 52 via the ducts 53 exits as bubbles in thewater which pass upwardly through the chamber 33 against the flow ofwater circulating through the chamber 33 in the opposite direction forflow through the return line 36 back to the chamber 12. Bubbles passingupwardly through the chamber 34 carry dirt and fat particles or otherimpurities in the water to the surface. In addition, the ozone reactoror generator unit 32 creates bubbles of ozone which also pass upwardlythrough the chamber 33 to sterilize and clean the water.

Bubbles upon reaching the surface of the water will froth up and createfoam which flows into the drain funnel 50 carrying the dirt and fatparticles through the drain pipe 51 to waste. The height of the drainfunnel 50 can be adjusted to vary the extent to which bubbles aredischarged and for this purpose may be supported adjustably on brackets57. Alternatively, the drain funnel 50 may be attached to floats 58 tosupport the funnel 50 at or adjacent the level of water within thechamber 33. The foam is thus collected just above the water level andflows out through the funnel 50 under the influence of gravity. Waterflowing outwardly from the chamber 33 and into the chamber 12 via theduct 36 and duct 37 creates a circulating flow of water in the chamber12 in an anti-clockwise direction (FIG. 3).

As the system 10 operates under low pressure, the foam fractionator 30can be cleaned without stopping operation of the system 10 andsimilarly, the ultraviolet light generators 41 can also be removed forreplacement of bulbs or repair whilst the system 10 continues to run.The ozone generator unit 32 can also be serviced whilst the system isoperating. This is facilitated by having the foam fractionator 30,ultraviolet unit 31 and ozone generator unit 32 arranged to one side ofthe chamber 12 in a truncated corner 22 or a wall of the chamber 12 andthus out of the main flow of water.

The swirl chamber 13 is of a generally hexigonal shape to assist in theswirling of water flow and receives water through the spillway 23 fromthe main chamber 12 which carries floating waste into the chamber 13.The spillway 23 enters the chamber 13 at the periphery thereof and at agenerally tangential orientation to induce into the chamber 13 acirculating or swirling flow. The outlet 27 which communicates with thebase of the chamber 12 through passage 26 also is directed generallycircumferentially or tangentially to induce swirling of flow of water inthe chamber. As the water level in the chamber 13 is below that in thechamber 12, water will flow from the chamber 12 into the chamber 13 fromthe top and bottom thus carrying wastes into the chamber 13. Theswirling flow of water will cause heavy particles fish and food waste tocollect centrally at the base of the chamber 13. A waste outlet 58 isprovided centrally in the base of the chamber 13, the waste outlet 54being connected by a duct 59 within the building floor slab and valve 60to waste (see FIG. 5), the valve 59 being opened at regular intervals toallow heavy particles to be discharged.

A water outlet 61 extends through a side wall 62 of the chamber 13 todirect water from the chamber 13 into the filter chamber 14, the wall 62being common to both chamber 13 and chamber 14. The outlet 61 is belowthe level of the spillway 23 and thus sets the normal level of water inthe chamber 13 below the level in the main chamber 12. A feed pipe 63 isreleasably coupled to the outlet 61 through a male/female connection andextends centrally and coaxially through a drum filter 64 for the finefiltering of the water flowing in from the swirl chamber 13. The drumfilter 64 as more clearly shown in FIG. 7 includes a pair of annular endmembers 65 joined by a plurality of longitudinally extending ribs 66which are spaced around a circumferential line arranged midway betweenthe inner and outer diameters of the annular members 65. The ribs 66which comprise flat strip-like members have their major dimension lyingin substantially radially extending planes as is apparent in FIG. 9 andsupport a fine filtering screen or mesh 67 which is wrappedcircumferentially around the ribs 66 and which is secured to the ribs 66such as by stapling. Each annular end member 65 is supported by and runin a pair of free running grooved guide wheels 68 which are rotatablymounted to a cradle or baffles 69 in the chamber to support the drumfilter 64 for rotation about a substantially horizontally axis whichextends longitudinally of the drum filter 64.

The incoming water through the feed pipe 63 as well as being fed to thedrum filter 64 for filtering is also used to rotatably drive the drumfilter 64. For this purpose, a series of spaced apart radial ducts 70extend from the feed pipe 63 and open adjacent the ribs 66. A baffle 71in the feed pipe 63 prevents water passing straight through the pipe 63.When water flows into the feed pipe 63 and out through the ducts 70 asat 72, it applies a force to the respective ribs 66 to thereby causerotation of the drum filter 64. In addition, water flowing out of theducts 70 is filtered for passage through the filter screen 67 as at 73.The end members 65 define through their annular configuration an innerannular lip 74 spaced radially inwardly of the filter screen 64. The lip74 prevents any water from running out of the open ends of the drumfilter 64 before passing through the screen material 67. In the extremecase of the water level rising within the drum filter 64, it cannot jamup the drum filter 64 by over filling as it will simply cascade over theend lips 74 and thus will not prevent the drum filter 64 from rotating.

For cleaning of the filter screen 67, a pair of ducts 75 and 76 areprovided above the drum filter 64 to extend longitudinally thereof. Oneduct 75 is connected to a water pump submerged in an end section 78 ofthe chamber 14 and has a plurality of spaced nozzles 79 through whichwater can be directed towards the screen 67 to wash the screen 67. Theother duct 76 is also provided with a plurality of spaced nozzles 80 andis connected to an air pump 81. Timers are associated with the waterpump 77 and air pump 81 to operate the pumps at regular intervals toforce pressurised water and air through the nozzles 79 and 80 and impactagainst the screen 67 to clean materials gathering on the screen 67.Materials displaced from the screen 67 are collected in a wastecollecting trough 82 which is of a hopper-like V-shaped cross sectionand which is arranged to extend within the drum filter 64 and centrallythereof beneath the cleaning water and air ducts 75 and 76. The wastecollector trough 82 receives materials displaced from the filter screen67 along with the water forced through the screen 67. The wastecollector trough 82 sits within a longitudinally extending slot 83 inthe feed pipe 63 and projects out of each end of the filter drum 64. Theopposite ends 84 of the trough 82 are flared outwardly in a funnel-likeconfiguration to catch all materials washed from the drum filter 64. Theend 84 adjacent the section 78 of the chamber 13 extends beyond thebaffle 71 and has an opening 85 therein which allows water and finematerials to be discharged into an extended portion 86 of the feed pipe63 beyond the baffle 71. The end of the extending portion 86 of the feedpipe 63 directs the collected waste into a drain pipe 87 which alsoserves as an overflow drain if the level of water in the chamber 13exceeds a predetermined level.

The cleaning ducts 75 and 76 provide the advantage of enabling cleaningof the filter screen 67 while the drum filter 64 it is running atfulfill capacity without stopping of water flow, or for any need tobypass the system. As the drum filter 64 rotates, air or water or bothdislodges any fine material clogging the screen 64 and blows or forcesit into the V section collector trough 82 for passage into the feed pipesection 86 and then to the drain pipe 87. Water flowing into the drainpipe 87 may be simply discharged to waste. Optionally, a filter bag 88may be connected to the pipe section 86 via a valve for collecting finesand filtering the collected waste water. The bag 88 may be removed andcleaned or replaced at regular intervals or when clogged or filled withwaste. Alternatively or additionally a filter device may be provided inthe drain pipe 87 so as to enable waste water to be recycled.

The drum filter 64 may be easily removed by detaching the feed pipe 63from the outlet 61 and when the pipe 63 is detached, the V-shaped wastecollector trough 82 is also detached being supported by the pipe 63. Thecleaning water ducts 75 and air ducts 76 can be simply folded down toopposite sides of the filter drum 64. After removal of the feed pipe 63and trough 82, the entire drum filter 64 can be removed. This means thatone drum filter 64 can be removed and another complete drum filter 64installed quickly if desired.

Water filtered by the drum filter 64 and flowing through the filterscreen 67 as at 73 passes to the lower portion of the chamber 14 whichcontains a bio-filter medium 89 to provide a surface for bacteria tolive on. Typically, the bio-filter medium 89 comprises a plurality ofelements upon or in which the bacteria may live. Typically the elementscomprises pieces of cokes however other elements or mediums may be used.The vertical baffles 69 which are preferably detachably received invertical slots 90 in opposite walls 91 of the chamber 14 (see FIG. 7)separate the chamber 14 into sections 92 containing the bio-filtermedium 89. The bio-filter medium 89 is supported by a supporting grid 93above the base 94 of the chamber 14. The chamber 14 is also providedwith drains 95 in each chamber section 92, the drains 95 being connectedto waste via a common duct 96 and valve 96′ which can be opened as andwhen required for draining or cleaning the chamber 14 (see FIG. 5)

One or more submergible pumps 97 are provided in the end section 78 ofthe chamber 14 to pump water from the chamber 14 to the main biologicaltank 15 via a duct 98. The pumps 97 operate continuously and cause thecirculating flow of water through the whole system 10 and further ensurethat the water pumped out of the chamber 14 is the same or greater thanwater entering the chamber 14 through the feed pipe 63 to therebymaintain the level of water in the chamber 14. The pumps 97 may also beused to augment the cleaning of the screen 67 of the drum filter 64through a branch line which can be opened to connect the pump or pumps97 to the spraying duct 75.

The tank 15 and as shown in FIG. 12 is in this embodiment of anelongated rectangular form is separated into a number of sections 99 bya series of upright baffles 100 supported removably in grooves in theside walls of the tank 15. A pair of spray bars 101 extendlongitudinally of the tank 15 and are connected to the duct 98 through aside wall of the tank 15 as at 102 to receive the water pumped from thechamber 14 by pump or pumps 97. The spray bars 101 contain a series ofoutlets in the form of openings 103 through which water exits to bedistributed over a bio-filter medium 104 arranged in each section 99 ofthe tank 15. In a further form, the spray bars 101 may compriserotatable spray bars which rotate about a vertical axis to distributethe water over the medium 104. The bio-filter medium 104 comprises aplurality of elements upon or in which the bacteria may live and whichfor example may be tubular elements arranged in an unordered mannerwithin the chamber sections 99. The elements may be arranged in meshbags to enable easy handling. The bio-filter medium 104 is supported onopen racks or grids 105 arranged above the base 106 of the tank 15 andto promote bacterial action, provision is made for forcing air throughthe tank 15. For this purpose, the tank 15 is provided with air pipes107 which extend longitudinally of the tank 15 and which are arrangedbeneath the racks 105. The air pipes 107 include a series of spacedopenings 108 for the exit of air and the pipes 107 are connected at 109to the air pump 56 through suitable connecting piping.

The base 106 of the tank 15 also includes an inclined section 110through which one or more water outlets 111 pass from through whichwater from the tank 15 is returned or recirculated to the main chamber12 (see FIG. 3). A pair of ducts 112 also pass through the tank 15 atopposite ends to communicate opposite ends of the building module 11with each other to maintain substantially constant climate conditionswithin the building 11. Air fans may be provided in the ducts 112 toensure circulation of air between opposite ends of the building module11. A further duct 113 through the tank 15 is provided for the passageof service lines such as electricity leads. The lids 20 which close thetank 15 are provided with air vents 114 (see FIG. 1) to allow venting ofgases such as carbon monoxide and carbon dioxide which are generated bythe biological medium 104. The base of the tank 15 is also provided witha number of recessed drain outlets 115 for draining of the tank 15 intothe waste pipe 87 in the chamber 14 via ducting 116 within the base ofthe tank 15 and an outlet 117 through the side of the tank 15.

In operation, water from the chamber 14 is pumped by the pumps 97through the spray bars 101 to be sprayed through the openings 103 overthe bio-filter medium 104 at the same time air at the temperature withinthe building module 11 is pumped by the air pump 56 through the airpipes 107 to exit through the openings 108 and pass upwardly against theflow of water over the medium 104. This serves to promote the biologicalfiltering action of the medium 104.

To control the temperature of air within the building module 11, areverse cycle air conditioner 118 is provided through a wall in thesection 16 of the building 11 over the main chamber 12 to enabletemperature within the building module to be controlled by heating orcooling. The conditioned air as well as circulating above the chamber 12also passes through the air ducts 112 into the region above the swirlchamber 13 and drum filter chamber 14. This maintains a substantiallyconstant temperature within the sections of the building module 11. Theair conditioner 118 as well as controlling the air temperature withinthe building module 11 also controls the temperature of the watercirculating through the system 10 as the air pumped by air pump/s 56through the water in the foam fractionator 30 and bacterial filter tank15 is derived from the air within the building module 11.

To maintain the level of water in the system 10 after drainage of waterfrom the respective drains or for any other reason, the main chamber 12includes a float controlled water outlet 119. A similar outlet 120 isprovided adjacent the drain filter chamber 14. The outlets 119 and 120are connected to a common supply line 121 (see FIG. 5) connected to apressurised water source. Thus if there is a drop in water level withinthe chamber 12 or chamber 14, water is automatically topped up throughthe outlets 119 and 120.

All of the pipes and plumbing which convey water through the buildingmodule 11 are moulded into the base and walls of the building modules asindicated for example in FIG. 5 and sealed such that the piping cannotleak or break. Further water supply pipes which are not moulded into thebase and walls are situated over the tanks or chambers themselves suchthat any loss of water through the pipes only leaks back into the tanksor chambers so that no water losses can occur. As all the maincomponents are integrally moulded or joined together such that watercannot leak between them, there is a substantial reduction in plumbing.In addition, a considerable amount of the flow is through gravity thusreducing energy consumption. With the panels or shutters 19 closed, fishcannot escape as they can only hit the walls of the building module 11and fall back into the chamber 12. Thus no netting or covering isrequired over the chamber 12. The shutters or panels 19 also provideweather protection when feeding fish within the chamber 12 or for otherservicing operations. As the system 10 is self contained within thebuilding module 11 and the system 10 is climate controlled, it can beplaced in many different environments such as in the tropics or snow orice and be immediately operational when connected to a power source.

The building module 11 being in modular form is portable to enable it tobe relocated or located on site however it will be appreciate that thebuilding 11 may be erected on a permanent concrete slab.

It will be appreciated that the building module 11 may be in manydifferent configurations whilst incorporating the main componentsthereof arranged as shown schematically in FIGS. 11, 12 and 13 wherelike components of the system of FIGS. 1 to 4 have been given likenumerals. FIG. 11 illustrates the drainage system where each tank orchamber can be drained to waste through suitable ducting and furtherindicates the different levels of water maintained within the respectivechambers and tanks as governed by operation of the pump/s 97. FIGS. 12and 13 illustrates the flow between the tanks or chambers where water inthe main chamber 12 flows into the swirl chamber 13, from the swirlchamber 13 into the drum filter chamber 14 under the influence ofgravity. Water is then pumped by pump/s 97 into the into the biologicalfilter tank 15 for return to the main chamber 12 through outlets 111 tothereby establish the circulating flow through the system 11.

FIG. 14 illustrates in exploded view three possible orientations of thebiological filter tank 15 relative to the main chamber 12, and filterchamber 14 and swirl chamber 13 which are arranged in reversedorientation from that shown in FIGS. 1 to 4. The resultingconfigurations of building modules 120, 121 and 122 are shown in FIG. 15with the tank 12 positioned along one side of and lengthways of thebuilding module 120 and above the main chamber 12, in FIG. 16 where thetank 15 is positioned centrally of the building module 121 and arrangedwidthwise above the main chamber 12, and in FIG. 17 where the biologicalfiler tank 12 is positioned alongside the main chamber 12.

In the embodiment of FIGS. 18 and 19, the building module 123 has themain chamber 12, swirl chamber 14, and drum filter chamber 14 arrangedas in FIGS. 1 to 4 but the biological filter tank 15 arranged above andto the back of the main chamber 12 and extending longitudinally. Anopening 124 in the side wall of the building module 123 above the filterchamber 14 can accept a side door or shutter 124 which supports the airconditioning unit 118. Alternatively, the opening 124 can be used togain access to the drum filter 64. A lid or cover 126 (shown in dottedoutline), covers the tank 15 whilst a hinged lid or cover 127 (shown indotted outline) covers the main chamber 12 to keep the sunlight out andassist in controlling the temperature and lighting artificially topromote maximum growth. As an alternative, the lid or cover 127 may bereplaced by a roof and wall section 16 of the type shown in FIGS. 1 and4 having a shutter 19 which allows access to the tank 12.

Referring now to FIGS. 20 to 23, there is illustrated an alternativeconfiguration of building module 128 having a main base unit 129incorporating the main chamber 12, and swirl chamber 13 and filterchamber 14. The chambers 12, 13 and 14 may be, as shown in dottedoutline, of a circular cross sectional configuration (as may thecorresponding components of the embodiments described above and below).The biological filter tank 15 (shown in dotted outline in FIG. 20)extends in this case over the main chamber 12 and swirl chamber 13 andmay include a permanent divider 130 to separate it from the space abovethe swirl chamber 13. In this case, the tank 15 is closed by a lid 131and the chamber 12 is closed by a pivotal lid 132 which incorporatessides 133 so as to fully enclose the space over the chamber 12 when thelid 132 is closed. The air conditioner 118 may be supported on a hingeddoor 134 at the end of the biological filter tank 15. FIG. 25illustrates in exploded view the manner in which the components of thebuilding module 128 may be assembled.

FIGS. 26 illustrate a pair of end sections 135 and 136 which may befitted to either end of the building module 11 of FIGS. 1 to 4 to createa building 137 which has additional security and weather protection foroperators. The end sections 135 and 136 have roofs 137 end and sidewalls 138 and 139, floors 140 and doors 141 in the end walls 129 suchthat operators can enter through the doors 41 to have access to oppositeend of the building module 11.

In the embodiment shown in FIG. 26, the end sections 138 and 139 areintegrally formed end sections. The end sections however may be formedas upper and lower halves as indicated by the dotted outline 142. As afurther alternative, the base unit 143 of the building module 11 may beextended along the dotted lines 142 to define lower halves of each endsection 135 and 136 incorporating the chambers 12, 13 and 14. The upperside of the building module 11 indicated at 144 may be extended at eachend along the dotted outlines to define the upper halves of the endsections 135 and 136. The building 137 may thus be in upper and lowerhalves 145 and 146 as shown in FIG. 29 which may be integrally moulded,the upper half being a roof section incorporating the tank 15 and thelower half the chambers 12, 13 and 14.

FIGS. 30 to 31 illustrate yet a further embodiment of building 147defining an aquaculture system which includes a full length roof section148 overlying a base section 149 which defines in this case the mainchamber 12, swirl chamber 13, filter chamber 14 and biological filtertank 15. Water flows from the main chamber 12 via the spillway 23 intothe swirl chamber 13 which also receives water from the base of thechamber 12 as before. Water in the swirl chamber 13 then passes to thedrum filter 64 and then chamber 14. The water in the chamber 14 thenpasses via duct 98 to the biological filter tank 15, water in the tank15 then being returned to the main chamber 12. Foam fractionators 30 areprovided adjacent the main chamber 12 as are ultraviolet units 31 andozone reactor units 32 for water treatment as before. The building 147is also provided with end sections 151 and 152 which provide shelteredwalkway areas to the system. The roof section 148 may define a hip roofas shown in dotted outline in FIG. 30 or a flat roof as illustrated. Theflat roof facilitates stacking of building modules 147 one on top of theother, side by side or cross stacked.

In the embodiment of building module 153 of FIGS. 33 to 35, the mainchamber 12, swirl chamber 13 and filter chamber 14 are arranged in afirst section 154 with a separate angled roof section 155 and thebiological filter tank 12 is defined by a separate unit 156 which may bepositioned in juxtaposition with the first section 154 as illustrated inFIGS. 35 and 36. The unit 156 is provided with a lid 157 which providesaccess to the interior of the tank 15, the lid 157 being angled whenclosed and matching the angled roof section 155. In this embodiment, thetank 12 has an increased height therefore a larger cleaning capacity.Shutters 158 in the walls of the roof section 155 can be opened provideselected access to the interior of the first section 154 for servicingof the components or monitoring operation of the system.

The building 153 of FIGS. 33 to 35 may be modified to have a flat roofso as to enable buildings 153 to be stacked. Thus the roof section 155may be flat as shown in dotted outline at 159 in FIG. 33 and the unit156 housing the biological filter tank 15 may also have a matching flatroof 160. To facilitate stacking, access to the tank 15 may be providedthrough a side shutter 161.

Whilst it is preferred that the parts of the aquaculture buildings areformed integrally where possible, an aquaculture building 162 may beconstructed from a series of modules as illustrated in FIGS. 36 to 39.Thus the main chamber 12 may be formed in a separate module 163 whichalso carries the foam fractionators 30, ultraviolet units 31 and ozonereactors 32 if required. The swirl chamber 13 may be formed in aseparate module 164, the drum chamber 14 in a separate module 165 andthe biological filter tank 15 as a separate module 166. The modules 163,164, 165 and 166 may then be butted up against each other to form thebuilding 163. Suitable plumbing is provided where required to enablecommunication between the modules by means of pipes moulded into thewalls and floors of the modules. A separate roof module 167 may also beprovided and assembled with the modules 163, 164, 165 and 166 to definea closed environment as shown in FIG. 39. The roof module 167 may defineaccess openings 168 closable by shutters as before allowing access tothe system but closing the system to maintain the closed environment.The roof module 167 as shown in FIG. 37 may define a hip roof oralternatively a flat roof as in FIG. 39 thereby allowing the building tobe stacked.

FIG. 40 illustrates a two level building 168 formed by a plurality ofcross stacked building modules 169 and 170 with the building modules 169at the lower level having flat roofs for example of the type describedwith reference to FIG. 30, 33, or 39 whilst the upper level modules 170may have hip roofs as illustrated or flat roofs. In the embodiment ofFIG. 41, twenty-five modules are arranged in stacks one above the otherin rows of five again with the lower modules 169 having flat roofs andthe modules 170 in the uppermost level having flat or hip roofs. It willbe appreciated that the modules 169 and 170 may be stacked in manydifferent configurations to form buildings of various sizes andconfigurations and where required, suitably walkways or verandahs 172may be provided between the modules. The modules 169 and 170 may operateas individual aquaculture systems or alternatively, the modules may belinked together so that the water circulates through all modules. Themodules may for example contain different types of fish or marineinvertebrates.

In the embodiment of FIGS. 42 to 45, the aquaculture building 173 hasthe main chamber or chamber unit 174 containing the chamber 12, swirlfilter chamber 13 and filter chamber 14 formed as a single unit with thebiological filter tank 15 although the components may be formedseparately and joined as in FIG. 35 and 36. The biological filter tank15 is of smaller size and closed by a hinged lid 175. A hip roof section176 is provided to overlie the main unit 176, the roof section 176having openings 177 providing access to the main unit 174, the openings177 being closable by shutters to define a closed environment or spaceover the chambers 12, 13 and 14.

In the embodiment of FIGS. 46 to 48 which is similar to the embodimentof FIGS. 42 to 45, a pair of biological filter tanks 15 are provided onopposite sides of the main unit 174, each of which is closable by a lid175. The tanks 12 may be formed integrally with the main unit 174 or asseparate modules attachable to the main unit 12. In each case air vents178 may be provided in the lids 175 for escape of gases generated by thebiological filter medium.

FIGS. 50 and 51 illustrate an alternative embodiment of aquaculturebuilding module 179 in which in this case the main chamber 180 is ofelongated form and includes a central divider 181 to form the chamber180 into an endless loop. Swirl chambers 13 which communicate with themain chamber 180 are formed in each end of the building module 179 beingof either hexagonal or circular configuration as illustrated. Inaddition, filter chambers 14 are formed adjacent to and communicatingwith the swirl chambers 13. Each chamber 180, 13 and 14 may be mouldedinto the base of the building 179 for example by concrete or fiberglassmoulding. The central divider 181 also is provided at opposite ends withfoam fractionators 30 which communicate with the main chamber 180 viaultraviolet units 31. Ozone reactors 32 (not shown) may also be providedin the central divider 181 to communicate with the foam fractionators30. Outlet ducts 37 from the foam fractionators 30 extend in thedirection of circulation flow around the chamber 180 to assist in thatflow. Biological filter tanks 15 are provided at each end of thebuilding 179 extending transversely of the main chamber 180, eachreceiving water from the adjacent drum filter chamber 14. Outlets 111from the tanks 15 direct water from the tanks 15 back into the mainchamber 180 in the direction of flow of water around the main chamber180. The building 179 includes a roof section 182 over all the chambers180, 13 and 14 and between the tanks 15 to define an enclosed climatecontrolled space. A walkway 183 provides access to the central divider181 from the side of the building 179 for servicing the components inthe divider 181 or monitoring operation of the system.

The aquaculture system defined by the building 179 functions in the samemanner as described above with fish or other marine invertebrate locatedwithin the main chamber 180 with water circulating around the mainchamber 180 in the clockwise direction. Water in the main chamber 180 issubject to treatment by the foam fractionators 30 and ultraviolet units31 (and ozone reactors 32 where employed). Water further flows to theswirl chambers 13 through spillways 23 and then to the filter drums 64for fine filtering. Water is then pumped from the chamber 14 to thebiological filter tanks 15 where it is subject to the biological mediumtherein and return to the main chamber 11.

In the embodiment of FIGS. 52 and 53, the building module 184 includesan elongated main chamber 185 having a central divider 186 however inthis case the foam fractionators 30, ultraviolet units 31 (and ozonereactors 32 where used) are provided at one end of the main chamber 185.A swirl chamber 13 and filter chamber 14 having a drum filter 64 areprovided at the opposite ends of the chamber 185. The biological filtertank 15 is provided adjacent the swirl chamber 13 and filter chamber 14extending transversely of the main chamber 185. Water is pumped to thetank 15 for treatment from the filter chamber 14 through pump lines 98whilst the outlet 111 from the tank 15 directs water back into the mainchamber 185. Sediment drains or collectors 187 defined by recess in thefloor of the main chamber 187 communicate through ducting 188 with theswirl chamber 13 which draws in the collected sediment. A roof and wallsection 189 defines a closed space over the chambers 185, 13 and 14 withthe climate in the space being governed by an air conditioning unit 118.A door accessible walkway 190 provides access to the central divider186. The sides of the roof and wall section 189 may be provided withhatches 191 providing access to the main chamber 185. This embodimentalso functions in the same manner as described above.

FIGS. 54 and 55 illustrate yet a further embodiment of building 191defining an aquaculture system according to the invention similar to theembodiment of FIGS. 52 and 53 however in this case three foamfractionators 30 and associated ultraviolet units 31 and ozone reactors32 are provided to communicate with the water in the main chamber 192.Water is drawn into the swirl chamber 13 by sediment drains 187 as inthe embodiment of FIGS. 52 and 53 however water passes from the filterchamber 14 through duct 193 back to the main chamber 192. In thisembodiment, a biological filter tank 15 is not employed with thisfunction being carried out by biological contactors which are in theform of paddle wheels 194 (in this case four) supported at spacedpositions in the main chamber 192 and being free for rotation abouthorizontal axes. The paddle wheels are substantially submerged withinthe water within the chamber 192 but rotate with circulating flowthrough the chamber. The paddle wheels 194 carry internally, abiological filter medium 195 to which the water in the chamber 192 iscontinually subject as it causes rotation of the paddle wheels 194.

In the embodiments of FIGS. 50 to 55, the building modules 179, 184 and191 are preferably formed as a separate lower section or moulding whichforms the main chambers and swirl and filter chambers 13 and 14 and aseparate roof section or moulding which is placed over and seals off thelower section to enable climate control and therefore temperaturecontrol of the water within the chambers and of the air pumped throughthe foam fractionators 30 and biological tank 15 where used. The mainchambers and swirl and filter chambers 13 and 14 however may be formedas separate units or mouldings which may be abutted with, and joined toeach other.

Referring now to FIG. 56, there is illustrated a further embodiment offoam fractionator 196 for use in the aquaculture system of theinvention. In this case, the separate ultraviolet chamber 39 iseliminated and the ultraviolet light generators 41 provided as a singletube set or a multiple tube set arranged circumferentially about thefunnel 50. The chamber 197 communicates through upper and lower ducts198 and 199 with the main chamber 12.

In the configuration of FIG. 57, the foam fractionator 200 has a foamcollector 201 which is in the form of an inverted cone which is locatedaround the sides of the fractionator chamber 202 so that the foam 203 iscollected around the outer sides of the chamber 202. Multiple outlets204 are provided to direct the collected foam 203 outwardly of thechamber 202 to waste. The foam collector 201 surround a centralultraviolet light generator 41 which kills pathogens and bacteria in thewater. It will be noted that in this embodiment, a submersible pump 30is provided in the chamber 202 to assist in flow of water back into themain chamber 12 through duct 205.

Referring now to FIGS. 58 and 59, there is illustrated a further form ofdrum filter arrangement for use in the aquaculture system of theinvention. The drum filter 206 is of similar construction to the filter64 of FIG. 7 in that it includes annular end walls 207 joined bylongitudinally extending ribs 208 around which a filter fabric ormaterial 209 is wrapped and secured. The filter 206 is also supportedfor rotation on spaced wheels 210 mounted to baffles 211 and the drumfilter 206 is supplied with water from the swirl chamber in by a feedtube 212 in a similar manner to that described with reference to FIG. 7except that openings 213 in the tube 212 permit water to pass downwardlyfrom the tube 212 through the filtering fabric 209 of the filter 206. Toeffect rotation of the drum filter 206, one or both ends walls 207 areprovided with a number of circumferentially spaced members 214 which maycomprise extension of the ends of the ribs 208 and be shaped tocooperate with water supplied through a feed tube 215. This actioneffects rotation of the drum filter 206 to continuously present a newsection of filter fabric 209 to the water exiting the openings 213. Aswith the embodiment of FIG. 7, air and water cleaning tubes 216 and 217are provided for spraying at timed intervals water or air through thefabric 209 for collection in the trough 218 for direction to the wastepipe 87.

As an alternative driving arrangement shown in FIG. 60, one or more ofthe guide wheels 210 may be driven by an electric or hydraulic motor 219via an endless belt or chain 220 to cause rotation of the driven wheel210 and thus the drum filter 206 to continuously present a new filteringsurface to incoming water. In yet an alternative arrangement shown inFIG. 61, the drum filter 206 may be directly driven by being coupledthrough a wheel or pulley 221 coaxial with the drum filter 206 and adrive belt or chain 222 to a drive motor 223.

The drum filters described in the above embodiments do not need or use avertical screen which reduces the area of mesh for the water to strainthrough, have no centre shaft or bearings, and do not need a specialouter housing. The drum filters can be mounted on a simple cradle andsuspended over the fish tank if required, and can clean themselveswhilst continuing to operate at full capacity. As the drum filters donot have a shaft, components can easily fitted within the interior ofthe filter. By incorporating the use of compressed air as well as water,the drum filter can clean continually or spasmodically which ever isrequired. The water and air bars can be set side-by-side for individualuse or incorporated into one. Other gases may be used for cleaningprovided they are non-toxic or polluting.

The drum filter systems described above may of course be used inaquaculture systems other than those described or in any other filteringapplication. Similarly the described foam fractionators (with or withoutassociated ultraviolet and ozone reactor units) may be employed in otheraquaculture systems.

In each of the above building modules, light sources 224 such asincandescent or fluorescent lights may be provided in space above themain chamber 12 to create artificial light conditions for growing offish or marine invertebrates. The light sources 224 may be controlled bytimers to create artificial day and night conditions to replicateexternal conditions.

The present invention thus provides a self contained aquaculture systemincorporated in and defined by a building which may be used in manydifferent environments. Further as the internal temperature within thebuilding can be simply and effectively controlled, control of the watertemperature in which fish or marine invertebrates are growing can alsobe controlled resulting in improved growing conditions and efficiency ofoperation.

1. A self-contained aquaculture system comprising a modular building,said building having a base section, a main water chamber for containingfish or marine invertebrates formed within said base section, said basesection having side walls, at least a portion of one of said side wallshaving an inner side and an outer side, said inner side comprisingportion of a side wall of said main chamber, said building furtherhaving a top section covering at least said main chamber and defining anenclosed space above said main chamber, water treatment means within atleast said base section of said building and adjacent said main chamberfor treating water from said main chamber, means for circulating waterfor flow from said main chamber through said water treatment means andback to said main chamber, and means for controlling the air temperaturewithin said enclosed space.
 2. A system as claimed in claim 1 whereinsaid top section includes a roof and side walls, said side walls of saidtop section being aligned with the side walls of said base section.
 3. Asystem as claimed in claim 1 wherein said base section and said mainchamber are moulded from a mouldable material and wherein said mainchamber is integrally moulded with at least part of said base section.4. A system as claimed in claim 1 wherein said water treatment meansincludes a primary filter and a secondary filter for filtering solidsfrom water in said main chamber.
 5. A system as claimed in claim 4wherein said primary filter comprising a second chamber which is locatedadjacent to said main chamber, first communicating means for connectingthe base of the main chamber to the second chamber whereby solidsgathering in the base of the main chamber may pass into the secondchamber and second communicating means connecting the main chamber tothe second chamber whereby water and solids may flow from the top levelof water in the main chamber into the second chamber.
 6. A system asclaimed in claim 5 wherein said second communication means comprises aspillway whereby water in said main chamber above the level of thespillway may flow into said second chamber.
 7. A system as claimed inclaim 4 wherein said secondary filter comprises a drum filter having ascreen or mesh filtering material, rotatable rollers externally of saiddrum filter for supporting said drum filter for rotation and means forconveying water from the primary filter to the interior of said drumfilter for passage through said screen or mesh material.
 8. A system asclaimed in claim 7 wherein said drum filter has means adapted tocooperate with said water conveyed from said primary filter to effectrotation of said drum filter.
 9. A system as claimed in claim 8 whereinsaid means adapted to cooperate with said water comprise a plurality ofcircumferentially spaced members and wherein said water conveying meanshas a water outlet or outlets adjacent said members.
 10. A system asclaimed in claim 9 wherein said circumferentially spaced memberscomprise a plurality of circumferentially spaced and longitudinallyextending ribs supporting said filter screen or mesh material andextending between a pair of end circular or annular members, said endmembers being supported on said rollers.
 11. A system as claimed inclaim 9 wherein said means for conveying water from the primary filterto the drum filter comprises a feed duct extending from said primaryfilter longitudinally within said drum filter, said feed duct includinga generally radially extending duct member having a said water outlet.12. A system as claimed in claim 11 wherein said feed duct is at a levelin said second chamber to maintain the water level therein beneath thewater level in said main chamber.
 13. A system as claimed in claim 7 andincluding means for cleaning said filter screen or mesh material, saidcleaning means comprising means above said drum filter for sprayingwater against said screen or mesh material and/or for applyingpressurized air against the screen or mesh material and there beingmeans internally of said drum filter for catching and collectingmaterials dislodged from the filter screen or mesh material andconveying said materials to waste.
 14. A system as claimed in claim 13wherein said means for catching said dislodged materials comprises ahopper internally of said drum filter, said hopper communicating with awaste line.
 15. A system as claimed in claim 7 and including a thirdchamber in said base section and wherein said drum filter is supportedover said third chamber such that water passing through said drum filtercollects therein, said third chamber including biological filter mediaand defining a first biological filter.
 16. A system as claimed in claim15 and including a further biological filter, said further biologicalfilter comprising a fourth chamber carrying biological filter media,means for conveying water from said third chamber to said fourth chamberand means for conveying water from said fourth chamber back to said mainchamber.
 17. A system as claimed in claim 16 wherein said means forconveying water from said third chamber to said fourth chamber includesmeans at the upper end of said fourth chamber for spraying said waterover said biological filter media and there being provided means forsupplying air to said fourth chamber for flow through said biologicalfilter media therein in a direction against water flow through saidbiological filter media.
 18. A system as claimed in claim 1 wherein saidwater treatment means includes at least one foam fractionator fortreatment of water in said main chamber, said foam fractionatorcomprising a chamber, an inlet to said foam fractionator chambercommunicating with said main chamber for receiving water therefrom, areturn line for returning water from said foam fractionator chamber tosaid main chamber, and means for supplying air to a lower portion ofsaid foam fractionator chamber for bubbling through water therein.
 19. Asystem according to claim 18 and including a funnel member in said foamfractionator chamber at or adjacent the upper level of water in the foamfractionator chamber for collecting bubbles or foam at the surface ofthe level of water, said funnel member being connected to waste andmeans for supplying air to said return line to assist in water flow backto the main chamber and circulation of water in the main chamber.
 20. Asystem as claimed in claim 19 and including an ultraviolet treatmentchamber connected to said main chamber and said foam fractionator inletwhereby water from the main chamber is subject to exposure toultraviolet light.
 21. A system as claimed in claim 20 wherein saidultraviolet treatment chamber is located in or adjacent said side wallof said main chamber and includes an ultraviolet light source, saidultraviolet treatment chamber including an inlet communicating with saidmain chamber and an outlet communicating with said inlet of said foamfractionator chamber.
 22. A system as claimed in claim 18 and includingan ozone reactor for supplying ozone to water in said foam fractionatorchamber for bubbling through water in said foam fractionator chamber.23. A system as claimed in claim 17 wherein air for supply to saidfourth chamber of said further biological filter chamber is provided byone or more air pumps which pump air from within said building at theinternal building temperature as determined by said air temperaturecontrolling means to thereby control the temperature of water in saidbiological filter chamber and thereby in said main chamber.
 24. A systemas claimed in claim 18 wherein air for supply to said foam fractionatoris provided by one or more air pumps which pump air from within saidbuilding at the internal building temperature as determined by said airtemperature controlling means to thereby control the temperature ofwater in said foam fractionator and thereby in said main chamber.
 25. Asystem as claimed in claim 16 wherein said fourth chamber of saidfurther biological filter is defined by a tank.
 26. A system as claimedin claim 25 wherein said tank is supported above said main chamber andwherein water conveyed from said fourth chamber back to said mainchamber flows under the influence of gravity back into the main chamber.27. A system as claimed in claim 1 wherein said means for controllingthe temperature in said enclosed spaced comprises air conditioningmeans.
 28. A self-contained aquaculture system comprising a modularbuilding, said building having a base section, a main water chamber forcontaining fish or marine invertebrates formed within said base section,a second swirl chamber comprising a primary filter formed in said basesection adjacent said main water chamber, means communicating said mainchamber with said second chamber for removing solids from water in saidmain chamber, fine filtering means comprising a secondary filter forreceiving water and filtering water from said second chamber, a thirdbiological filter chamber formed within said base section adjacent saidsecond chamber for receiving water from said fine filtering means, saidbuilding module further including a top section or sections coveringsaid main water chamber, and said second and third chambers and definingan enclosed space or spaces over said chambers, means for circulatingwater for flow from said main chamber through said second chamber, finefiltering means and said third chamber back to said main chamber, andmeans for controlling the air temperature within said enclosed space orspaces.
 29. A system as claimed in claim 28 wherein the level of waterin said third chamber is maintained lower than the level of water insaid second chamber and the level of water in said second chamber ismaintained lower than the level of water in said main chamber wherebywater flows from said main chamber to said third chamber under theinfluence of gravity.
 30. A system as claimed in claim 28 and includinga further biological filter chamber, said further biological filterchamber being defined by a biological filter tank, said tank beingarranged adjacent to the main chamber or above the main chamber.
 31. Asystem as claimed in claim 28 wherein said main chamber includes a sidewall and wherein one or more foam fractionators are provided in oradjacent said side wall, the or each said foam fractionator including aninlet communicating with said main chamber for receiving water from saidmain chamber and an outlet communicating with said main chamber forreturn of water to said main chamber.
 32. A system as claimed in claim28 wherein said main chamber is of elongated configuration and a centraldivider is provided therein such that flow circulates around the centraldivider and wherein said primary and secondary filters are provided atone or both ends of said main chamber.
 33. A system as claimed in claim32 wherein one or more foam fractionators for treatment of water in saidmain chamber are arranged in said central divider, the or each said foamfractionator having an inlet and outlet communicating with said mainchamber.
 34. A system as claimed in claim 28 wherein said base sectionis moulded from concrete or other mouldable material and wherein saidchambers are formed integrally in said base section.
 35. A system asclaimed in claim 30 wherein said biological filter tank is formed as aseparate unit moulded from concrete or other mouldable material.
 36. Asystem as claimed in claim 35 wherein said top section or sectionsinclude said biological filter tank supported above said main chamberand one or more roof and wall sections which cooperate with saidbiological filter tank to define enclosed spaces over said main chamber,and second and third chambers.
 37. A system as claimed in claim 30wherein said biological filter tank is formed as a separate unit whichextends to the full height of said modular building and wherein said topsection includes one or more roof or wall sections defining an enclosedspace over said main, second and third chambers.
 38. A system as claimedin claim 28 wherein said chambers are moulded as separate units, saidunits being assembled by being abutted against each other to form saidbase section and wherein said top section comprises a roof and wallsection which covers and encloses said assembled chambers.
 39. A systemas claimed in claim 30 wherein one or more biological filter tanks areprovided to one or both sides of the main chamber and second and thirdchambers, said main chamber, second and third chambers being covered andenclosed by a top section comprising a roof and wall section and whereinsaid biological filter tank or tanks are covered with separate roofs orlids.
 40. A system as claimed in claim 28 wherein said top section orsections of said modular building has a flat roof whereby modularbuildings may be stacked one above the other to form a multi-levelbuilding.
 41. A system as claimed in claim 28 wherein said finefiltering means comprises a drum filter supported externally forrotation and wherein said second chamber includes an outlet extendinginto the interior of said drum filter which maintains the level of waterin said second chamber lower than the level of water in said mainchamber.
 42. A system as claimed in claim 41 and including a furtherbiological filter chamber, pump means for pumping water from said thirdchamber to said further biological filter chamber and for maintainingthe level of water in said third chamber below the level in said secondchamber, and means for conveying water in said further filter chamberback to the main chamber.
 43. A self-contained aquaculture systemcomprising a portable modular building, said building having a basesection, a main water chamber for containing fish or marineinvertebrates, said main water chamber being moulded integrally with atleast part of said base section, said building further having a topsection covering at least said main chamber and defining an enclosedspace above said main chamber, water treatment apparatus within at leastsaid base section of said building and adjacent said main chamber fortreating water from said main chamber, means for circulating water forflow from said main chamber through said water treatment apparatus andback to said main chamber, and means for controlling the air temperatureof water within said main chamber.
 44. A self-contained aquaculturesystem as claimed in claim 43 wherein said base section includes aintegrally moulded chamber comprising a swirl chamber adjacent said mainchamber and communicating with said main chamber for receiving watertherefrom, said swirl chamber comprising said water treatment apparatus.45. A self-contained aquaculture system as claimed in claim 44 whereinsaid water treatment apparatus includes a rotatable drum filter having ascreen or mesh filtering material and means for conveying water fromsaid main chamber to said drum filter.
 46. A self-contained aquaculturesystem as claimed in claim 44 wherein said base section includes anintegrally moulded biological filter chamber for containing a biologicalfilter media, and means for supporting said drum filter above saidbiological filter chamber whereby said biological filter chamberreceives filtered water from said drum filter.
 47. A self-containedaquaculture system as claimed in claim 46 wherein said water treatmentapparatus includes a further moulded biological filter chamber forcontaining a biological filter media, means for conveying water from thefirst biological filter chamber to said further biological filterchamber and means for returning water from said further biologicalchamber to said main chamber.
 48. A self-contained aquaculture system asclaimed in claim 46 wherein said part of said base section containingsaid main water chamber is moulded as a module separate from said swirlchamber and biological filter chamber.